Functionalization Of Single-walled Carbon Nanotubes Research Articles

Enhancing mechanical and interfacial properties of PEEK/epoxy/SWCNT composites employing aromatic hydroxyl and amine-functionalized SWCNTs

Employing epoxy polymer and pristine and aromatic amine and hydroxyl functionalized SWCNTs in poly(ether ether ketone) (PEEK), novel polymer nanocomposite models were created. Molecular dynamics (MD) simulations were used to explore the interfacial, mechanical, and structural features of single-walled carbon nanotube (SWCNT) reinforced PEEK/epoxy matrix (BM) systems. We used MD simulation techniques to show how covalently functionalizing SWCNTs and blending PEEK with a polymer containing hydroxy‑functional groups can improve the interfacial and mechanical properties of PEEK nanocomposites. This study showed that –CH2C6H4NH2, –CH2C6H4OH group grafted SWCNT improve the interfacial and mechanical properties of PEEK-based nanocomposites due to the formation of hydrogen bonds between the filler materials and the polymer matrix, as well as better filler dispersion into the polymer matrix. The improvement of properties of polymer nanocomposites depends on the extent of the interaction of nanoparticles with the polymer matrix. Aromatic amine and hydroxyl (-CH2C6H4NH2, and -CH2C6H4OH) functionalization of SWCNTs is required for their high-performance engineering applications. Because epoxy polymer has a great ability to form hydrogen bonds with fictionalized SWCNT, adding 10% epoxy polymer to the BM increased the interfacial strength, elastic modulus, and shear modulus of SWCNT composites. This study provides a novel technique to improve the properties of polymer nanocomposites by covalently functionalizing SWCNTs.

Quantum defects as versatile anchors for carbon nanotube functionalization.

Single-wall carbon nanotubes (SWCNTs) are used in diverse applications that require chemical tailoring of the SWCNT surface, including optical sensing, imaging, targeted drug delivery and single-photon generation. SWCNTs have been noncovalently modified with (bio)polymers to preserve their intrinsic near-infrared fluorescence. However, demanding applications (e.g., requiring stability in biological fluids) would benefit from a stable covalent linkage between the SWCNT and the functional unit (e.g., antibody, fluorophore, drug). Here we present how to use diazonium salt chemistry to introduce sp3 quantum defects in the SWCNT carbon lattice to serve as handles for conjugation while preserving near-infrared fluorescence. In this protocol, we describe the straightforward, stable (covalent), highly versatile and scalable functionalization of SWCNTs with biomolecules such as peptides and proteins to yield near-infrared fluorescent SWCNT bioconjugates. We provide a step-by-step procedure covering SWCNT dispersion, quantum defect incorporation, bioconjugation, in situ peptide synthesis on SWCNTs, and characterization, which can be completed in 5-7 d.

Physical Characterization and Material Properties of Epoxy Matrix Nanocomposites Containing Functionalized Single-Walled Carbon Nanotubes

Physical Characterization and Material Properties of Epoxy Matrix Nanocomposites Containing Functionalized Single-Walled Carbon Nanotubes

Noncovalent Functionalization of Single-Walled Carbon Nanotubes with a Photocleavable Polythiophene Derivative.

Single-walled carbon nanotubes (SWCNTs) have received extensive research attention owing to their extraordinary optical, electrical, and mechanical properties, which make them particularly attractive for application in optoelectronic devices. However, SWCNTs are insoluble in almost all solvents. Therefore, developing methods to solubilize SWCNTs is crucial for their use in solution-based processes. In this study, we developed a photocleavable polythiophene-derivative polymer dispersant for SWCNTs. The noncovalent surface functionalization of SWCNTs with a polymer allows their dispersal in tetrahydrofuran. The resultant solution-processed polymer/SWCNT composite film undergoes a hydrophobic-to-hydrophilic change in surface properties upon light irradiation (313 nm) because hydrophilic carboxyl groups are formed upon photocleavage of the hydrophobic solubilizing units in the polymer. Furthermore, the photocleaved composite film displays a 38-fold increase in electrical conductivity. This is due to the removal of the solubilizing unit, which is electrically insulating.

Flexible Chemiresistive Cyclohexanone Sensors Based on Single-Walled Carbon Nanotube-Polymer Composites.

We report a chemiresistive cyclohexanone sensor on a flexible substrate based on single-walled carbon nanotubes (SWCNTs) functionalized with thiourea (TU) derivatives. A wrapper polymer containing both 4-vinylpyridine (4VP) groups and azide groups (P(4VP-VBAz)) was employed to obtain a homogeneous SWCNT dispersion via noncovalent functionalization of SWCNTs. The P(4VP-VBAz)-SWCNT composite dispersion was then spray-coated onto an organosilanized flexible poly(ethylene terephthalate) (PET) film to achieve immobilizing quaternization between the pyridyl groups from the polymer and the functional PET substrate, thereby surface anchoring SWCNTs. Subsequent surface functionalization was performed to incorporate a TU selector into the composites, resulting in P(Q4VP-VBTU)-SWCNT, for the detection of cyclohexanone via hydrogen bonding interactions. An increase in conductance was observed as a result of the hydrogen-bonded complex with cyclohexanone resulting in a higher hole density and/or mobility in SWCNTs. As a result, a sensor device fabricated with P(Q4VP-VBTU)-SWCNT composites exhibited chemiresistive responses (ΔG/G0) of 7.9 ± 0.6% in N2 (RH 0.1%) and 4.7 ± 0.4% in air (RH 5%), respectively, upon exposure to 200 ppm cyclohexanone. Selective cyclohexanone detection was achieved with minor responses (ΔG/G0 < 1.4% at 500 ppm) toward interfering volatile organic compounds (VOC). analytes. We demonstrate a robust sensing platform using the polymer-SWCNT composites on a flexible PET substrate for potential application in wearable sensors.

(Invited) Tailored Functionalization of Single-Walled Carbon Nanotubes for Real-Time Monitoring of Hydrolytic Enzymes Activity

Single-walled carbon nanotubes (SWCNTs) have unique optical and physical properties, and they benefit from the ease of surface functionalization and biocompatibility. Semiconducting SWCNTs fluoresce in the near-infrared (nIR) part of the spectrum, which overlaps with the transparency window of biological samples. The SWCNTs fluorescence is sensitive to the environment, and depending on the surface functionalization, subtle changes in the proximity of the nanotube can result in significant spectral modulations. Hence, SWCNTs can be utilized as optical sensors enabling real-time detection with optical signal transduction1–3. Here, we demonstrate tailored functionalization of SWCNTs, which render the nanotubes substrate for hydrolytic enzymes. We show that the chemical composition and functional groups of the SWCNTs wrapping mediate the interaction between the nanotube and the enzymes. Our results open new avenues for monitoring enzymatic activity with fluorescent nanoparticles and hold great promise for biomedical research and applications.Reference(1) Hendler-Neumark, A.; Bisker, G. Fluorescent Single-Walled Carbon Nanotubes for Protein Detection. Sensors 2019, 19 (24), 5403.(2) Bisker, G.; Bakh, N. A.; Lee, M. A.; Ahn, J.; Park, M.; O’Connell, E. B.; Iverson, N. M.; Strano, M. S. Insulin Detection Using a Corona Phase Molecular Recognition Site on Single-Walled Carbon Nanotubes. ACS Sensors 2018, 8 (2), 367–377.(3) Bisker, G.; Dong, J.; Park, H. D.; Iverson, N. M.; Ahn, J.; Nelson, J. T.; Landry, M. P.; Kruss, S.; Strano, M. S. Protein-Targeted Corona Phase Molecular Recognition. Nat. Commun. 2016, 7, 1–14.

(Invited) Molecular Structure-Based Photoluminescence Modulation of Locally Functionalized Single-Walled Carbon Nanotubes Using Bis-Aryl Functionalization

Single-walled carbon nanotubes (SWCNTs) show photoluminescence (PL) in the near infrared (NIR) region, which is applicable to bioimaging and telecommunication devices. Recently, local chemical functionalization of SWCNTs has been developed to enhance their NIR PL properties, in which defects such as sp3 carbon are locally doped to the crystalline sp2 carbon network of the tube walls by the functionalization.[1-3] Actually, E 11* PL of the locally functionalized SWCNTs (lf-SWCNTs) is observed with red-shifted wavelengths and increased quantum yields compared to original E 11 PL of pristine SWCNTs. It is due to formation of new emissive sites with narrower band gaps and exciton trapping features in the tube structures.In the local chemical functionalization, doped site structures of the lf-SWCNTs can be changed depending on modifier molecules, which results in effective modulation of the NIR PL wavelengths of the lf-SWCNTs beyond 1000 nm-region. Previously, we have developed bis-aryldiazonium salts (bAs) that have two reactive aryldiazonium groups connected with a methylene linker and observed E 11 2* PL over 1200 nm regions from the lf-SWCNTs with (6,5) chirality based on its proximal aryl functionalization.[4]Here, we synthesize new modifier molecules with the bis-aryldiazonium motif and modify the geometry of the proximal aryl-functionalized sites of the lf-SWCNTs. As a result, for example, methylene linker positions on the aryldiazonium groups of bAs clearly changed the trend of methylene length-dependent wavelength shifts of E 11 2* PL. [5] Moreover, bAs having rigid linker structures changed peak positions of E 11 2* PL, indicating that the control of the proximal defect configuration would be an effective way for the PL property modulation of lf-SWCNTs. As another aspect of the proximal aryl functionalization, we found that E 11 2* PL showed unique wavelength shift behaviors by microenvironment changes using various organic solvents. The observed trend was different from those of E 11 PL and E 11* PL[6], in which proximal defect distances could be an important factor for their microenvironment responsiveness.Therefore, molecularly designed bis-aryldiazonium modifiers become promising tools to create structurally controlled bis-aryl functionalized sites of lf-SWCNTs and precisely modulate their NIR PL wavelengths (> 1000 nm).[1] T. Shiraki et al. Acc. Chem. Res., 53, 1846 (2020). [2] S. Tretiak et al., Acc. Chem. Res., 53, 1791(2020) [3] Y. Wang et al. Nat. Rev. Chem., 3, 375 (2019). [4] T. Shiraki et al. Sci. Rep., 6, 28393 (2016). [5] T. Shiraki et al. Chem. Lett., 48, 791 (2019). [6] T. Shiraki et al. Chem. Commun., 55, 3662 (2019). Figure 1

Effect of electrochemical functionalization of single-walled carbon nanotube electrodes in flexible enzymatic biofuel cells

We report a flexible enzymatic biofuel cell based on electrochemically functionalized single-walled carbon nanotube (SWNT) electrodes. Comparative studies on the impact of the electrochemical functionalization of the SWNT electrodes on the device performance revealed a 40%–110% increase in power density as compared to that of the device with as-fabricated SWNT electrodes, with an observed maximum power density of 7.2 μW cm−2. This improvement in performance can be attributed to the increase in the amount of enzymes adsorbed on the SWNT surface and the enhanced electron transfer rate owing to the SWNT functionalization. Our findings can aid improve the performance of flexible and high-power-density biofuel cells.

Investigation on the effect of functionalization of single-walled carbon nanotubes on the mechanical properties of epoxy glass composites: Experimental and molecular dynamics simulation

In recent decades, polymer composites are widely used in industry due to their good mechanical properties and their low specific weight. Also, the use of glass fibers and carbon nanotubes can strengthen and improve the mechanical performance of the polymer due to their good mechanical properties. In this study, incorporated glass/epoxy nanocomposite with carbon nanotubes (CNT) samples were fabricated using a hand lay-up process, and the effect of addition functionalized Single-Walled Carbon Nanotubes (F-SWCNT) with COOH and non-functionalized SWCNT was investigated. The tensile strength, elastic modulus, bending strength was obtained experimentally using SANTAM-STM50. X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) were used to investigate the phase and morphology of the fibers. The mechanical properties results showed that the highest elastic modulus and tensile strength are obtained for the sample reinforced with F-SWCNT which increased by 32% and 10%, respectively in comparison with pure epoxy. Also, the obtained results of the bending test indicate that the highest flexural modulus and the highest flexural strength are related to the sample reinforced with functionalized carbon nanotubes which are 16.9 GPa and 381.39 MPa, respectively. Then, the mechanical performance of the reinforcement in the epoxy matrix and the failure mechanism was monitored using SEM images. Finally, reinforced epoxy nanocomposites with functionalized and non-functionalized SWCNT were simulated using Molecular Dynamics (MD) simulation to examine the agreement with the trends of experimental results. The MD obtained results showed that the most appropriate mode of dispersion occurs when functionalized carbon nanotubes are used. Also, it was observed that the elastic modulus of incorporated nanocomposites with F-SWCNT increased by 17% compared to non-functionalized SWCNT which shows the agreement with the trends of experimental results.

A stabilization of the electrospun, modified polyacrylonitril with functionalized single-walled carbon nanotubes

In the present study, poly (acrylonitrile-co-methyl methacrylate), P (AN-co-MMA), nanofibers and P (AN-co-MMA) nanofibers with Functionalized Single-Walled Carbon Nanotubes (F-SWCNTs) were produced by electrospinning and became stabilized. Besides, samples were evaluated using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), a Scanning Electron Microscope (SEM), and X-ray diffraction (XRD). In the sample containing F-SWCNT, the amount of the heat released during stabilization reactions was lower than that with pure PAN copolymer nanofibers. This indicates that the F-SWCNTs prevent damage and sudden release of heat to the nanofibers during the stabilization process. Besides, the carbon nanotubes (CNTs) greatly prevent a decrease in the diameter of the nanofibers the size of the crystals, and the arrangement of the nanofibers during the stabilization process.

Sp3-Functionalization of Single-Walled Carbon Nanotubes Creates Localized Spins.

Chemical functionalization-introduced sp3 quantum defects in single-walled carbon nanotubes (SWCNTs) have shown compelling optical properties for their potential applications in quantum information science and bioimaging. Here, we utilize temperature- and power-dependent electron spin resonance measurements to study the fundamental spin properties of SWCNTs functionalized with well-controlled densities of sp3 quantum defects. Signatures of isolated spins that are highly localized at the sp3 defect sites are observed, which we further confirm with density functional theory calculations. Applying temperature-dependent line width analysis and power-saturation measurements, we estimate the spin-lattice relaxation time T1 and spin dephasing time T2 to be around 9 μs and 40 ns, respectively. These findings of the localized spin states that are associated with the sp3 quantum defects not only deepen our understanding of the molecular structures of the quantum defects but could also have strong implications for their applications in quantum information science.

Enhancement of functionalized carbon nanotubes gas sensor by adding metal oxide nanoparticles

Functionalized-multi wall carbon nanotubes (F-MWCNTs) and functionalized-single wall carbon nanotubes (F-SWCNTs) were well enhanced using CoO Nanoparticles. The sensor device consisted of a film of sensitive material (F-MWCNTs/CoONPs) and (F-SWCNTs/CoO NPs) deposited by drop- casting on an n-type porous silicon substrate. The two sensors perform high sensitivity to NO2 gas at room temperatures. The analysis indicated that the (F-MWCNTs/CoONPs) have a better performance than (F-SWCNTs/CoONPs). The F-SWCNTs/CoONPs gas sensor shows high sensitivity (19.1 %) at RT with response time 17 sec, while F-MWCNTs/CoONPs gas sensor show better sensitivity (39 %) at RT with response time 13 sec. The device shows a very reproducible sensor performance, with high repeatability, complete recovery, and adequate response. A demonstration of the improvement in sensing of NO2 gas using CoO-functionalized nanotubes is provided.

Biomolecule Exchange Dynamics on Carbon Nanotubes Via Multiplexed Fluorophore Quenching

Adsorption of biomolecules on single-walled carbon nanotubes (SWCNTs) has enabled developments in molecular sensing, in vivo imaging, and gene delivery applications.1,2 This noncovalent functionalization of SWCNTs preserves the pristine SWCNT atomic structure, thus retaining the intrinsic near-infrared fluorescence for sensing or imaging functions, and offers a reversible binding mode for cargo delivery. However, biomolecule adsorption is an inherently dynamic process, where exchange occurs between molecules in the bulk solution and molecules on the nanoparticle surface, into what is known as the corona phase. The nature, strength, and kinetics of both the biomolecule binding and unbinding processes on SWCNTs are important contributors to the success of SWCNT-based technologies. Understanding this binding process is especially important for intended uses of functionalized SWCNTs in biological environments, where native biomolecules such as proteins compete with the original biomolecule to occupy the SWCNT surface. Such biofouling of the SWCNT surface disrupts the intended functionality of the nanoparticle and can further lead to adverse biocompatibility outcomes.We present a generalizable method to study the corona exchange dynamics between solution-phase and corona-phase biomolecules on SWCNTs in real-time.3 This approach exploits the quenching property of fluorophores proximal to the SWCNT surface to monitor ligand binding and unbinding events. Real-time tracking of adsorption and desorption events on the SWCNT surface are conducted with systematic variation of the molecular entities and solution conditions, with a specific focus on DNA (as the sensing moiety) and protein (as the biofouling agent). Binding profiles are extracted from the experimental assay and used to inform a kinetic model of the system. The work presented herein develops an understanding of the fundamental corona exchange mechanism and provides insight into performance of these designed SWCNT-based systems in biologically relevant, protein-rich conditions. References Demirer, G. S. et al. High aspect ratio nanomaterials enable delivery of functional genetic material without DNA integration in mature plants. Nature Nanotechnology 1 (2019) doi:10.1038/s41565-019-0382-5.Beyene, A. G. et al. Imaging striatal dopamine release using a nongenetically encoded near infrared fluorescent catecholamine nanosensor. Science Advances 5, eaaw3108 (2019).Pinals, R. L., Yang, D., Lui, A., Cao, W. & Landry, M. P. Corona Exchange Dynamics on Carbon Nanotubes by Multiplexed Fluorescence Monitoring. J. Am. Chem. Soc. (2019) doi:10.1021/jacs.9b09617. Figure 1

Room Temperature NO&lt;sub&gt;2&lt;/sub&gt; Gas Sensor Based on Functionalized Carbon Nanotubes /Nickel Oxide Nanoparticles

Functionalized-multi wall carbon nanotubes (F-MWCNTs) and functionalized-single wall carbon nanotubes (F-SWCNTs) were well enhanced using NiO Nanoparticles. The sensor device consisted of a film of sensitive material (F-MWCNTs/ Nickel oxide nanoparticles) and (F-SWCNTs/ Nickel oxide nanoparticles) deposited by drop casting on n-type porous silicon substrate. The two sensors perform high sensitivity to NO2 gas at particular temperatures. The analysis indicated that the (F-MWCNTs/NiONPs) have a better performance than (F-SWCNTs/NiONPs). The F-SWCNTs/NiONPs gas sensor shows high sensitivity (18.2 %) at RT with response time 16 sec, while F-MWCNTs/NiONPs gas sensor show better sensitivity (45 %) at RT with response time 26 sec. The device shows a very reproducible sensor performance, with high repeatability, complete recovery and adequate response. A demonstration of the improvement in sensing of NO2 gas using NiO-functionalized nanotubes is provided.

Precisely tailoring the thermodynamic compatibility between single-walled carbon nanotubes and styrene butadiene rubber via fully atomistic molecular dynamics simulation and theoretical approach

From the perspective of thermodynamics, the compatibility between filler and matrix determines the dispersion and morphology of filler and further determines the final properties of composites. At present, it is difficult to obtain a quantitative relationship between the surface chemistry of filler and compatibility with matrix through experimental means. In this study, the quantitative relationship between functional groups and Hildebrand (δT) and two-component solubility parameters (δvdW, δele) of single-walled carbon nanotubes (SWCNTs) was obtained by molecular dynamics (MD) simulation. The most notable conclusion is that with the increase of grafting ratio, the δT and δvdW of SWCNTs first decrease, reach a minimum and then increase. This regularity makes the SWCNTs with different functional groups exhibit different compatibility behaviors with styrene butadiene rubber (SBR), resulting in different functionalization principles for different groups. Two-component solubility parameters of SWCNTs and SBR were further proved to be able to predict well their compatibility by Flory-Huggins model. Each functional group has the optimum grafting ratio at which the compatibility is the best. Additionally, the –CH3, –CH(O)CH– and –OH functionalized systems exist the optimum temperature for the best compatibility. The multifunctional groups is superior to a single group for the compatibility. This study provides a quantitative guidance for the functionalization of SWCNTs towards the good compatibility with SBR.

Detection of chirality of single-walled carbon nanotubes on hexagonal boron nitride

Single-walled carbon nanotube (SWNT) has attracted widespread attention for its unique one-dimensional atomic structure and outstanding physical and chemical properties. For both fundamental research and practical applications, it is critical to figure out the chirality of SWNT because the electronic band structure and the consequent electrical and optical properties are determined by its chirality. Here, we found that the chirality of SWNT on an insulating hexagonal boron nitride (h-BN) substrate can be obtained in a quick and concise manner through measuring the aligning direction and the diameter of SWNT. Additionally, Rayleigh scattering spectroscopy is conducted to confirm the obtained chirality. The developed technique for direct detection of chirality of SWNT on an insulating h-BN substrate could advance the study of chirality-dependent functional SWNT devices and the applications of SWNT related to chirality.

Carbon Nanotube-Based Stretchable Hybrid Material Film for Electronic Devices and Applications.

To meet the increasing demand, for stretchable conductive materials in a wide range of applications, innovative conductors based on single wall carbon nanotubes (SWCNT) self-grafted on different polymer films, are assembled. Aiming at a simple technology for flexible and stretchable electronic devices, and contrary to what commonly reported for carbon nanotubes (CNT), no chemical functionalization of SWCNT is necessary for stable grafting onto several polymeric surfaces. The novelty and functionality of our composite materials stand in the synergy among the intrinsic biocompatibility of CNT, a fully inert material, their electrical conductivity, and the stretchable-viscoelastic properties of the polymer-nanotube bundles composites. Electrical characterization of both unstretched and strongly stretched planar film conductors is provided, demonstrating the use of this new composite material for technological application. Also, an insight into the mechanisms of strong adhesion to the polymer is obtained by scanning electron microscopy (SEM) of the surface composite. As an example of technological application of such stretchable circuitry, the electrical functionality of a carbon nanotube-based six-sensor (electrode) grid is used to record subdural electrocorticograms in freely-moving laboratory rats over approximately three months.

Functional Single-Walled Carbon Nanotubes for Anion Sensing.

We report an anion-sensing platform wherein conductance changes are triggered by chemical interactions between selectors and anions. The selector design incorporates both a cationic moiety (i.e., pyridinium) and a thiourea-based dual-hydrogen-bond donor. Anion binding by a model selector (2) was studied using 1H NMR and UV-vis titrations, which reveal a binding strength toward acetate ions (AcO-) followed by Cl- > Br- > NO3-. These studies reveal that selector 2 is deprotonated upon addition of AcO-, whereas it undergoes hydrogen bonding associated with Cl-, Br-, and NO3-. The cationic pyridinium moiety improves anion binding affinity by lowering the pKa value of selector 2 and enhancing the hydrogen-bond donor capability as confirmed by spectroscopic titrations and DFT calculations. The selector is covalently attached to poly(4-vinylpyridine) (P4VP), which wraps single-walled carbon nanotubes (SWCNTs) (i.e., P4VP-2-SWCNT) to transduce an electrical signal. As a result, continuous anion sensing was achieved with high sensitivity represented by a normalized resistance change of 101.9 ± 10.3% toward 16.7 mM AcO-, whereas negligible sensitivity was observed toward Cl-, Br-, and NO3-. The sensitivity transition was attributed to the internal charge transfer of 2 by deprotonation of the thiourea proton upon addition of AcO-.

Green sonochemical synthesis, kinetics and functionalization of nanoscale anion exchange resins and their performance as water purification membranes.

This paper reports on sonochemically catalyzed atom transfer radical polymerization (SONO-ATRP) polyelectrolyte synthesis and chain-end functionalization to single-walled carbon nanotubes (SWCNT). This all aqueous process is kinetically facile without use of initiator, or reducing agents and with very low concentrations of catalyst. The process achieves high functionalization density of polymer onto the SWCNTs. These functionalized nanoscale resins (NanoResins) exhibit high performance as fast and sustainable water purification materials. SONO-ATRP of vinyl benzyl trimethyl ammonium chloride (vbTMAC) was performed in aqueous medium resulting in short polyelectrolyte strands with high atom economy and high monomer conversions (93%) at room temperature using a thin probe sonicator (144Wcm-2, 20kHz, for 4h). Kinetics analysis showed first order kinetics with respect to monomer concentration in presence of or absence of sonication power. Low temperature SONO-ATRP functionalization of SWCNTs is achieved within two hours without added reducing agent while similar functionalization density using reducing agents without sonochemistry required 12h under reflux conditions. Functionalized NanoResin membranes were tested against surrogate analyte and demonstrated high performance Thomas Model breakthrough curves with a maximum adsorption capacity of 139±1 mgg-1 and water flux of 692 Lm-2h-1bar-1 at one atmosphere pressure. Moreover, these materials are easily regenerated and reused without loss of performance or degradation.

The Impact of Covalent Functionalization on Single-Walled Carbon Nanotube Biosensor Fluorescence and Function

Single-walled carbon nanotubes (SWCNTs) are advantageous signal transduction elements for biological imaging and sensing due to their notable fluorescence in the near-infrared (NIR) region with minimal light absorbance by water or scattering by tissue (1). Recently, exciting developments in SWCNT surface chemistry have shown the retention and improvement of fluorescence intensity in SWCNTs after covalent surface functionalization (2). These chemistries provide chemical handles for specific attachment of molecules of interest to the SWCNT surface while keeping the intrinsic SWCNT NIR fluorescence intact for bioimaging and sensing applications. However, despite their unperturbed fluorescence, it is unclear whether functionalized SWCNTs maintain their ability for molecular sensing, which necessitates a modulation in SWCNT fluorescence provided by the molecular recognition of a noncovalently surface-adsorbed polymer. We compare the photophysical properties of functionalized SWCNTs to their pristine counterparts, and show SWCNT optical properties remain available for sensing applications, however with noted attenuation of fluorescence modulation between certain surface coating and analyte pairs. Molecular recognition provided by phospholipid SWCNT surface coatings maintain their ability to detect molecular analytes such as fibrinogen and insulin. Conversely, DNA oligonucleotide surface coatings under-perform for molecular recognition of dopamine compared to sensors constructed from pristine SWCNTs. We also discuss the use of covalent handles to tune the intrinsic properties of the SWCNT surface for use as biological tools. Lastly, we explore the application of covalently functionalized SWCNTs as dual-functional nanoparticles with both targeting and sensing capabilities. Our work establishes the potential advantages and drawbacks of covalent SWCNT functionalization, despite preservation of SWCNT fluorescence, and implications for applications in molecular sensing.(1) Bonis-O’Donnell, J. T. D.; Page, R. H.; Beyene, A. G.; Tindall, E. G.; McFarlane, I. R.; Landry, M. P. Dual Near-Infrared Two-Photon Microscopy for Deep-Tissue Dopamine Nanosensor Imaging. Adv. Funct. Mater. 2017, 27 (39), 1–10.(2) Setaro, A.; Adeli, M.; Glaeske, M.; Przyrembel, D.; Bisswanger, T.; Gordeev, G.; Maschietto, F.; Faghani, A.; Paulus, B.; Weinelt, M.; et al. Preserving π-Conjugation in Covalently Functionalized Carbon Nanotubes for Optoelectronic Applications. Nat. Commun. 2017, 8, 1–7.